Within the context of petroleum drilling and well completions, wells are typically constructed by drilling the well bore using one tubular string, largely comprised of drill pipe, then removing the drill pipe string and completing by installing a second tubular string, referred to as casing, which is subsequently permanently cemented in place. The installation of casing, in this typical construction requires that the casing be run into long boreholes, some having horizontal stretches. In these horizontal stretches, the casing must be installed by pushing it along the borehole. In so doing the casing is pushed in engagement with the borehole wall.
Recent advances in drilling technology have enabled wells to be drilled and completed with a single casing string, eliminating the need to ‘trip’ the drill pipe in and out of the hole to service the bit and make room for the casing upon completion of drilling. This change is motivated by potential cost savings arising from reduced drilling time and the expense of providing and maintaining the drill string, plus various technical advantages, such as reduced risk of well caving before installation of the casing.
However, casing installation through deviated wellbores or by drilling with casing challenge the performance requirements of the casing. Installation can place severe structural demands on casing since they must survive extended periods of time in contact with the borehole wall.
A device is needed to facilitate installation of casing either during a standard run in operation or when the casing is used for drilling.